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The health care worker was in Sierra Leone, one of the hotbeds of Ebola

The patient is not currently ill nor contagious, but had "high-risk exposure" to Ebola

(CNN) —  

An American health care provider working in Sierra Leone who had a “high-risk exposure” to the Ebola virus arrived at Nebraska Medicine on Sunday for “observation and possible treatment,” the center said.

“This patient has been exposed to the virus but is not ill and is not contagious,” said Dr. Phil Smith, medical director of the biocontainment unit at the Omaha medical center.

“However, we will be taking all appropriate precautions.”

Nebraska Medical Center, part of Nebraska Medicine, is one of only four hospitals in the United States that has biocontainment units and has been practicing for years to treat a highly infectious disease such as Ebola.

The other three hospitals are Emory University Hospital in Atlanta; Rocky Mountain Laboratories in Montana; and the National Institutes of Health in Maryland.

Nebraska Medical Center has treated three patients with Ebola:

Dr. Rick Sacra, who was infected while working in Liberia, was treated and released in September. NBC freelance cameraman Ashoka Mukpo, who was also working in Liberia, was treated and released in October. And Dr. Martin Salia, who was gravely ill when he arrived from Sierra Leone, died after less than two days of treatment in November, Nebraska Medicine said.

Nebraska Medicine said the patient who arrived Sunday was transported in a private air ambulance.

“This patient will be under observation in the same room used for treatment of the first three patients and will be carefully monitored to see if Ebola disease develops,” Smith said.

While the United States had 10 patients with Ebola last year, the situation in West Africa remains far more dire.

More than 7,500 people died from Ebola in 2014, the World Health Organization said. The vast majority of deaths were in Liberia, Sierra Leone and Guinea.